Thaws--periods of warming that interrupt winter processes--occur
on Lake Michigan coastal dunes during the winter and early spring.
Above-freezing temperatures change dune conditions during and after
the thaw.

During
the thaw:

Frozen ground thaws
from the surface down, most often resulting in a layer of damp
sand on top of a frozen sand layer.

Slope instability
in thawed or wet sand produces small mass movements such as flows
and slumps.

Melting snow and ice
produce meltwater which ponds at the surface if drainage is prevented
by frozen ground.

After thaws, sand movement
by wind occurs by cold-season processes: exposed sand moves if it
is released from frozen ground by sublimation or impact. Increased
water in the frozen ground (from meltwater during the thaw) strengthens
the cementation of frozen sand and slows down the rate of sand grain
release by sublimation.